This contains additional tests for multimedia.py

Specifically, this commit adds three tests that check the current state
A corner case of the STOP state is checked: if self.multimedia is null
it should not be in the STOP state

Issue #437
PR #469

Added current state tests for test_multimedia.py

Resolved flake8 errors.

recovered from last push; modified test to use constants

Removed trailing whitespaces - flake8

Added a type check for set window id; fails test

Changed int check for winId to None check; added None check for set_audio_feedback

Added tests to check multimedia.player states.

Fixed flake8 error

Attempted to test load_backend, but need to revisit

Began testing load_backend; waiting on mentor input on potential bug before proceeding

removed invalid tests

removed type error check in multimeda.py's set window id and feedback handler

cleaned up commented code; ready to squash

changed self.config to config

Contains tests for multimedia.py; ready to be merged.

This contains additional tests for multimedia.py